Vapor barrier for hollow walls, and method of installing same



W. S. MILES April 16, 1957 VAPOR BARRIER FOR HOLLOW WALLS, AND METHOD OF INSTALLING SAME Filed D90. 10, 1953 2 She ets-Sheet 1 iavililiarnialllaaiLLi Hil iar I I I I I l ulfl ql l u l I I L I I I I 1..

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BY/(/ 0 ATTORNEY April 16, 1957 w. s. MILES- VAPOR BARRIER FOR HOLLOW WALLS, AND METHOD OF INSTALLING SAME! Filed Dec. 10, 195a-- 2 Shqets-She'et 2 ATTORNEY United States Patent VAPOR BARRIER FOR HULLQW WALLS, AND METHOD OF INSTALLING SAME William S. Miles, Hastings on Hudson, N. Y., assignor to Johns-Manville Corporation, New York, N. Y., a corporation of New York Application December 10, 1953, Serial No. 397,316 12 Claims. (Cl. 20-101) The present invention relates to vapor barriers and methods of installing them in the space within hollow building walls, and to wall constructions including such vapor barriers and thermal insulation material in the interior wall spaces.

The invention relates more particularly to the problem of providing a vapor barrier in an existing inter-stud, inter-wall-face space or inter-frame-member, inter-wallface space; i. e., an interior wall space, such as occurs between adjacent studs or framing members and the two wall faces spaced thereby from each other, and especially where one wall face is a cold face, such as an exterior face of a building, andthe other is a warm wall face, such as a plastered interior face, and it is desired to fill the space between the cold and warm faces and the studs with insulating material. In this type of wall construction, thereis the danger that warm moist air, penetrating the warm face, will condense on the inside surface of the cold face in such quantities as to, in time, cause damage to the insulating material and, more seriously, the wood sheathing or the like forming the exterior face. The invention is particularly concerned with the elimination of this danger by providing for the installation ofa vapor barrier interiorly of the wall next to the warm face to prevent the passage of the vapor to the cold face. In its broader aspects, however, the invention relates to vapor barriers and their method of installation in hollow walls wherever such vapor barriers may be desirable. i

The problems mentioned above in connection with the insulation of the space between a warm wall face and a'cold wall face are discussed in greater detail in United States Patent No. 2,263,070, issued November 18, 1941, to Edward F. Cusick. This patent suggests the formation of the vapor barrier by spraying a moistureimpermeable compound on the inside surface of the Wall faces, but this method has the disadvantage of requiring special spraying apparatus and of being relatively time consuming and expensive, and does not guarantee complete'coverage because of difliculties in manipulating the nozzle to position to cover all the desired areas.

An alternative solution has been suggested in United States Patent No. 2,252,578, issued August 12, 1941, to Harry D. Powell. This patent discloses the insertion of an empty moisture-proof bag in collapsed condition through an opening in the exterior wall face at the top of the space or chamber to be insulated, whereupon the bag is pneumatically inflated and filled with the insulating material. disadvantages inherent in the method disclosed in the Cusick patent, it has certain disadvantages of its own. It has proved to be a somewhat awkward operation to stuff a collapsed bag of the size required through the aperture in the wall face and into the space to be insulated. A more serious disadvantage is that in the process of installing and inflating the bag it may become snagged on nails, etc. and punctured thereby. This in- While this method eliminates some of the so that the ridges on the inside faces 2,788,552 Patented Apr. 16, 1957 2 creases the installation problems and decreases the eifectiveness of the barrier when installed.

It is an object. of the present invention to overcome the difficulties mentioned above by providing a simple, inexpensive, and effective vapor barrier in compactly folded form and a method of installing it in an interior wall space of a building.

It is a further object of the invention to provide an insulated hollow building wall construction containing an improved vapor barrier. i

Other objects of the invention will become apparent from the detailed description that follows, taken in connection with the accompanying drawings, in which: i

Fig. 1 shows a side view, partly in elevation and partly in section, -of a portion of a building, looking toward the outside surface of an exterior wall face thereof, and illustrating the manner of installation ofmy novel vapor barrier and the insulating material;

Fig. 2 is a view in vertical section, taken on the line 2-2 of Fig. 1;

Fig. 3 is a view in horizontal section, taken on the line 3-3 of Fig. 1;

Fig. 4 is a view showing details of the vapor barrier shown in Figs. 1 and 2, collapsed on fold lines therein, and looking at its lower end; i

Fig. 5 is a view of the vapor barrier, similar to Fig. 4, but showing the folds partially opened up;

Fig. 6 is an enlarged fragmentary view in elevation of a portion of the vapor barrier completely opened up, with a side flap thereof against a stud, looking at the inside face of the body portion of the barrier;

, Fig. 7 is an enlarged fragmentary View of the vapor barrier of Figs. 1-6 opened up in plane development to show the fold lines; i

Fig. 8 is a view similar to Fig. 7 and showing an alternative manner of placing a longitudinal fold line to facilitate the folding of a base sheet to form the 'vapor barrier;

Fig. 9 is a view similar to Fig. 4, but showing the vapor barrier in an intermediate stage of the development of the folds; and, i

Fig. 10 is a view similar to Figs. 7 and 8 but illustrating the fold lines provided by the'method of folding shown in Fig. 9.

Referring more particularly to the drawings, vapor barrier 2 comprises a sheet of flexible vapor-impermeable material, such as heavy kraft paper coated on one or both sides or impregnated with a bituminous or other moisture-proof material or lined with a thin, heat-refiective, and vapor-impermeable metallic foil. A sheet of the type described, and preferably in substantially rectan gular strip form, is folded by any suitable procedure, such as illustrated by the fold lines appearing on Figs. 6 and 7 and discussed in greater detail hereinafter, to provide a folded article shown most clearly in Figs. 4 and 5, having side flaps 4 opposite eachother and folded back toward each other on the same face of the sheet 7, hereinafter referred to as the inside face thereof, along longitudinal fold lines 6. Between the side flaps is a body portion 8 having substantially parallel transverse fold lines 10 forming alternate ridges 12 and valleys 14 extending transversely of the body portion. The transverse fold lines extend into the side flaps and form ridges at 16 and valleys at 18 on the inside faces thereof extending from the longitudinal fold lines as continuation respectively, of the valleys 14 and ridges 12, in the body portion,

and side flaps are received with-in the valleys in the inside faces of the side flaps and body portions, respectively. It will be noted that the longitudinal fold lines 6 are zigzag lines reversing their direction at their points of intersection 20, 22 with each transverse fold line 10, and

of the body portion that thepcints' of intersection 20 of the longitudinal fold lines'6 with the ridges 12 on the inside face of the body portion lie closer to the lateral edges 24 of the sheet than the points of intersection 22 of the longitudinal fold lines" with the valleys in the inside face of the bodyportion. Stated another way, the ridges 1'2 6n the inside face-of the body portion and the ridgesld on the inside faces of the side flaps are longer than the valleys 14 in: the inside face of the body portion and the valleys 18 on the inside faces of the side flaps, respectively, and ridges 12 and 16 terminates respectively at points 20 and 22 on the longitudinal fold lines 6,- at which points the longitudinal fold' line's reverse direction in zigzag fashion. With the sheet folded as described, it canbe opened up' longitudinally on itstransverse fold lines,'with the result that the folds-iii the side flaps are automatically and simultaneously opened up and the side flaps erected to extend away from the inside face of the body portion at substantially right angles thereto, as shown in Figs. 1; .3, and 6. V i v The fold lines may be so arranged that terminal fl'aps 26 and 28 are provided at each end of the sheet, these terminal flaps being turned inwardly, as best shown in Figs. 2 and 5. At least one terminal flap, 28 as illustrated, is secured to the sheet, either to the body portion or to the side flaps thereof as shown, by any suitable means such as staples 30, in a manner to extend inwardly at'an angle tothe inside face of the body portion and to provide a pocket 32 open toward the other end of the sheet for releasably receiving an elongated weight 58. The pocket 32 can be formed in any other suitable way, as by'the use of an extension of the body portionturned back on itself and secured thereto, or by a separate envelopes'ecur'ed to the end of the body portion.

As previously stated, any suitable procedure and order of providing the fold lines to obtain the specific folded construction described may be employed. One convenient method of providing the fold lines will be clear from an examination of Fig. 7 in conjunction with Fig. 5. This method involves initiating the formation of the side flaps by first folding lateral edge portions of the fiat sheet inwardly toward each other on the same face (the inside face)v of the sheet al'ongstraight auxiliary longitudinal fold lines 34 spaced inwardly from each lateral edge of the sheet. With these flaps held against the inside face of the sheet, the transverse folds -are formed successively, reversing the direction of-fold at each fold line '10, taking care to have the terminal flaps 26 and 28 turned inwardly as described above. When the sheet has been thus folded,

the side flaps will not open out to erect themselves automatically upon the opening up of the sheet longitudinally on, the transverse fold lines. In order to obtain this re sult, itis necessary to complete the formation of the side flaps to the final form described above, in which they arejoined to the body portion on zigzag fold lines instead of straight fold lines, with the ridges 16 formed on the inside face of the side flaps by the initial folding steps being extended farther, and preferably substantially e'qual'distances, beyond fold lines 34. This means that the portions of the yalleys 14 inwardly adjacent the auxiliary longitudinal fold lines 34 must be reverse-creased to formfridge portions 36 between the auxiliary fold lines and the functional zigzag longitudinal fold lines 6. This extension of the ridges 16 to include the ridge portions 36, and the provision of the zigzag fold lines to form inplane development substantially similar pairs of right triangles havinga common side corresponding to a ridge portion 36 on the inside face of a side flap can be accomplished by forming these reverse creases and folds individually.

It will be obvious that an alternative method could includetheextension of the ridges 12 outwardly beyond fold lines 34, reverse-creasingthe portions of the valleys 18 of the initially formed side flaps to form the ridge portions'36 'Th-is variation in the method of folding, would produce fold lines in plane development as illustrate'din Fig. 8.

As an alternative to completing the folded article by forming the reverse creases and folds individually, the initially folded sheet, folded on the auxiliary longitudinal fold lines 34 and on the transverse fold lines 10, can be held in tightly folded condition, and a triangular corner portion 38 thereof adjacent each side of the body portion can then be folded back tightly as shown in Fig. 9 against one of the end flaps on a fold line 40 running from a point 42 on a fold line 10 spaced inwardly of the fold line 34 to a point 44 on fold line 34 spaced therealong from the fold line 10 and falling at a corner of the folded sheet, that is, on the intersection offold line 34 with a transverse fold line 10 that is to form a ridge 12 on the inside face of the body portion. It.will be noted that the inwardly spaced point 4-7. must fall on a fold line 10 which forms a valley 14 in the inside face of the body portion. When opened up in plane development, the fold lines will then appear as illustrated in Fig. 10. With the fold lines thus formed, and the side flaps erected from the inner face on the fold lines 34, it is only necessary to reverse-crease certain portions of the final zigzag longitudinal fold lines 6 from ridge to valley status, along with the reverse-creasing of portions 36, to obtain the final folded article.

In all'of the above-described methods of forming the folded vapor barrier, the auxiliary fold lines are formed principally as a matter of convenience in achieving the final folded form and are of course not required for the successful functioning of the completed article, and it is to be understood that all of the functional folds (i. e., the folds on lines 6 and the folds on lines 10 in both the body portion and side flaps) can be formed individually without forming the fold lines 34 or any of the other auxiliary fold lines. In all instances, the effect of the auxiliary fold lines is substantially nullified by flattening out the creases on thoselines. Some advantage is obtained, however, by leaving the creases on lines 34 in partial effect, since, as will later be inore apparent, they can be made to function to provide substantially straight line contact between the side flaps and the studs in an interior wall space, after the sheet has been opened up longitudinally and the side fl-aps erected on the zigzag lines, by drawing the ends of the unfolded sheet apart with su'fficient force to partially override the effect of the zig zag fold lines which, by the time th'e sh'eet is fully opened up longitudinally, have performed their essential function of erecting the side flaps. The straight line contact between the barrier and studs is desirable but not essential, because the seal between the barrier and studs need not be entirely comple'te to be effective. Furthermore, as will become apparent, the filling of the interwall-face, inter-stud space with insulation urges the side flaps into continuous contact withlthe studs over at least a portion of the area of the side fiaps adjacent their free edges, thus smoothing out any slight gaps between these edges and the studs.

Leaking now more particularly at Figs. 1.3, the manher of installing the novel vapor barrier described above in an existing building wall will be readily apparent, In this case, the wall structure is conventional, comprising, vertical studs 44, cross members '46 between the studs, an interior, warm wall face formed by plaster 48 applied to lath 50, and an exterior or cold wall face formed by sheathing 52 and overlapping courses bf shingles 54. As illustrated, a shingle, or shingles, may be removed at the upper portion of 'an inter-wall-face, inter-stud space in which the vapor barrier is to be applied, and an opening 56 formed throughthe'sheathing, preferably 'just below a cross member 46. A weight 58, which is long enough to extend substantially across the width of the body portion of the vapor barrier, :and to one end of which a retrieving line 60 is attached, is inserted in the pocket 32 of the vapor barrier. The latter is then insorted through the opening in folded condition, with the inside face of the barrier toward the opening'and the end of the barrier in which the weight is received positioned downwardly. The weight may then be gradually lowered while the upper end of the barrier is held at the top of the interior wall space or chamber, with the result that the vapor barrier is opened up longitudinally on its transverse fold lines, while at the same time the side flaps are automatically erected. It is convenient to secure the upper end of the barrier to the adjacent cross member or studs, by the use of staples or any convenient means, prior to lowering the weight to open up the barrier. The length and width of the vapor barrier in the unfolded condition which it assumes upon installation should conform to the length and width of the individual wall chamber which is to receive the barrier, these dimensions, of course, being determined by the space between the cross members and the studs, respectively. When the relative dimensions are as described, the side flaps erect against the studs, and at least portions of the terminal flaps of the barrier can be placed in contact with the cross members when installed. The weight brings at least the inner portion of the lower terminal flap into substantially line contact with the lower cross member along the lowermost transverse fold line 10. As stated above, the upper terminal flap can be secured to the upper cross member in any suitable manner. With the barrier opened up and in the position described, insulating material 61, such as mineral wool, can be filled or blown into the chamber through a nozzle illustrated in part at 62, with the result that the outside faces of the body portion, side flaps, and terminal flaps are held in position as described against the warm wall face, studs, and cross members, respectively. The weight can be retrieved before the filling operation is begun, or at some stage thereafter, when the insulating material is functioning to some extent to hold the lower portion of the barrier in position. If desired, an expendable weight could be used in the pocket of the barrier or otherwise secured to the lower end thereof and left in position in the wall. By employing a weight that is heavy enough to extend the barrier lengthwise under sufficient force to partially override the effect of the zigzag fold lines, substantially straight line contact between the side flaps and the studs can be obtained, as mentioned above, along the auxiliary longitudinal fold line 34, whether or not insulation is applied. This has certain obvious advantages, including the more effective prevention of the passage of the warm moist vapors from the interiorw-all face through the slight gaps between the side flaps and the studs, and the prevention of sitting of the insulation into those same gaps when introduced into the wall chamber. In any event, the gaps are slight, and it is not essential that the straight line contact condition be obtained between studs and side flaps, particularly since the same effect will be provided upon the filling of the space with the insulation, where employed. It is also not essential that the terminal flaps be provided for the specific purpose of making contact with the cross members, this being merely a refinement of the novel vapor barrier which is desirable to increase its sealing effectiveness to some extent.

When the installation has been completed as described, the entrance opening 56 is plugged as at 56 and the shingle or shingles replaced. A completed installation is illustrated in the chamber viewed at the left of Fig. 1. The middle chamber in Fig. l is shown being filled with insulation, with the vapor barrier in place. In the chamber viewed at the right of Fig. 1, the weight has extended the vapor barrier to its proper position.

From the above description, it will be evident that I have obtained the objects of my invention. While I have described my invention in rather full detail, it will be understood that these details need not be strictly adhered to but that various changes and modifications may sug gest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What I claim is:

1. A vapor barrier adapted for insertion against one wall of an inter-wall-face, inter-stud chamber in a building having hollow walls comprising, a folded sheet of flexible vapor-impermeable, material having side flaps opposite each other and folded along longitudinal fold lines toward each other on the same face of the sheet, and a body portion between said side flaps having transverse fold lines forming alternate ridges and valleys extending transversely thereof, said transverse fold lines extending into said side flaps and forming ridges and valley-s therein extending from said longitudinal fold lines as continuations, respectively, of the valleys and ridges in said body portion, so that the continuations of the ridges and valleys on the inside face of said body portion become valleys and ridges, respectively, on the inside faces of said side flaps, said longitudinal fold lines being zigzag lines reversing their direction at their points of intersection with each transverse fold line, the points of intersection with the ridges on the inside face of said body. portion lying closer to the lateral edges of said sheet than the points of intersection with the valleys in the inside face of said body portion.

2. The invention defined in claim 1, and said sheet having a pocket at one end thereof for receiving a weight, whereby said one end can be lowered in the chamber to open up the sheet on said fold lines and automatically erect said side flaps.

3. In an inter-wall-face, inter-stud chamber in a building, a vapor barrier as defined in claim 1 opened up on said transverse fold lines, with its side flaps erected, and so dimensioned and shaped that said body portion -sub-' stantially covers the area of one wall face of the chamber, said body portion and side flaps having their inside faces directed inwardly of the chamber and their outside faces in contact with said one wall face and studs, respectively.

4. The invention defined in claim 1, and a terminal flap at one end of said sheet folded back at an angle thereto and secured thereto to form a pocket for releasably receiving a weight, whereby said one end can 'be lowered in the chamber to open up the sheet on said fold lines and automatically erect said side flaps.

5. A method of providing a vapor barrier in an interwall-face, inter-stud chamber in a building comprising, providing a folded article as defined in claim 4, so dimensioned and shaped that its body portion substantially covers the area of one of the wall faces of the chamber when the sheet is opened up on its transverse fold lines, inserting a weight in said pocket of said article, inserting said article in folded condition through an aperture in the upper portion of one wall of the chamber, with the end of the sheet carrying said weight being disposed downwardly, and securing the other end of the sheet at the top of the chamber with its outside face disposed toward one wall thereof and lowering the Weight and said one end of the sheet to the bottom portion of the chamber to open up the sheet on its fold lines and to place said side flaps against said studs.

6. The invention as defined in claim 1, including a first terminal flap at one end of saidsheet turned inwardly and secured thereto to extend at an angle thereto and provide a pocket open toward the other end of the sheet for releasably receiving a weight, and an inwardly turned terminal flap at the other end of said sheet.

7. In a building wall construction comprising spaced vertical studs and spaced cross members extending therebetween, and spaced wall faces on opposite sides thereof spanning the space therebetween and defining therewith an inter-wall-face, inter-stud chamber, a vapor 'barrier as defined in claim 6 in said chamber, opened up on said transverse fold lines and so dimensioned and shaped that said body portion substantially covers the area of one wall face of the chamber, said body portion, side flaps, and "terminal flaps having their inside faces directed in- Wardly of the chamber, said side flaps and terminal flap-s having their (outside faces against said studs and said cross members, respectively.

8. The invention defined in claim 7, in which said one wall faceis a warm wall face, and the other wall face is a cold Wall face, and insulating material in said chamber between-said body portion and said cold wall face and between said sideflaps and terminal flaps.

#9. A'vapor barrier adapted for insertion against one wall face of an inter-frame-me'mber, inter-wall-facc, chamber'in a building having hollow walls comprising, a folded sheet of flexible vapor-impermeable material having a substantially rectangular strip form in plane development and having side flaps opposite each other and folded along longitudinal fold lines toward each other on the same face of the sheet, and a body portion between said side flaps having transverse fold lines form ing alternate ridges and valleys extending transversely thereof, said transverse fold lines extending into said side flaps and forming ridges and valleys therein extending from said longitudinal fold lines as-continuations, respectively, of the valleys and ridges in said body portion, so that the ridges on the inside faces of said body portion and side flaps are received Within the valleys in the inside faces of said side flaps and body portion, respectively, the ridges on the inside faces of said body portion and side flaps being longer than the valleys in the inside faces of said body portion and side flaps, respectively, and termi nating at points on said longitudinal fold lines, said longitudinal fold lines reversing direction at said points in zigzag fashion, whereby, when said folded strip is opened out longitudinally, the folds in said side flaps are automatically opened up and the side flaps erected to extend away from the inside face of said body portion.

10. The invention as defined in claim 9; and a terminal flap at one end of said body portion folded on one of said transverse fold lines back toward 'the inside face of said body portion and secured to said side flaps to form a pocket open toward the other end of said body portion for releasably receiving a weight.

11. The inpention as defined in claim 10, and the other and of said body portion terminating in an inwardly turned flapfor engagement with a framing member.

12. in a building construction comprisingspaced studs and warm andcold wall faces on opposite sides of said studs spanning the space therebetween' and forming therewith an inter-wall-face, inter-stud chamber, a vapor barrier as defined in claim 9 in said chamber, opened up on said transverse fold lines and so dimensioned and shaped that said body portion substantially covers the area of said warm wall face, said body portion and-side flaps having their inside faces 'di'rec-ted inwardly of the chamber and their outside faces in contact with said warm wall face and studs, respectively, and insulating material within said chamber between said body portion, side flaps, and cold wall face.

References Cited in the file of this patent UNITED STATES PATENTS 2,101,836 Benedict Dec. 14, 1937 2,251,585 Finch Aug. 5, 1941 2,252,578 Powell Aug. 12, 1941 2,312,301 Turner et a1. Mar. 2, 1943 

